ancient cucumbers!

[Joe Botting]

Hi all,
As a little starter, while this place gets going, we couldn't resist mentioning a recent find (on Easter Sunday, indeed) from near Llandrindod. It's a little yellow blob, 5 mm across, with a small ring at one end. (We've got a photo and will post it just as soon as we get round to following Roy's instructions...)
All in all, a remarkably unobtrusive little thing, but it turns out this is by some margin the oldest known holothurian (sea-cucumber) that is preserved complete; there are a few isolated, microscopic plates known from a similar age, but a complete specimen is an extremely rare thing. (Holothurians are an odd group of echinoderms, closely related to sea-urchins, but more elongated. Their shell has been reduced to thousands of microscopic sclerites, which are just about visible in our specimen, under a microscope. Today, they're a very successful group, and most of the living species are happiest trundling over the abyssal ocean floor.)
As I said, these fossils are meant to be very rare. The question is, how many people look for things like this? The specimen is from a classic trilobite locality (Bach-y-Graid) that has been intensely collected, of the age that used to be called Llandeilo. It's possible that it's just a one-off find from a single bed; but then again, maybe it isn't. A couple of other indeterminate-looking smears turned out to be complete sponges; both they and the cucumber have a lot of detail when you get them under a microscope.

So how many of you have found little blobs that you don't know what to do with, and therefore ignored? (There's no shame in that - professional palaeontologists are sometimes the worst culprits, because they have a fixed 'search image' of whatever group they study.) We're really very interested in this, for many reasons. Most of the really unusual, rare and new discoveries from the area recently have been among overlooked groups of fossils. I'm trying, among other things, to put together a 'complete' list of Builth Inlier fossils, which will go up on the webpage. It's at about 300 species at the moment, but every time we go back there's another dozen new ones, and most of them are obscure. Are we really only seeing the tip of the iceberg? Is the 'diversity' of any locality much as has been described, or are there dozens of other things being studiously ignored..?

So grab your handlenses, get those slabs out of your attic, and let us know what you think. It might be useful to look particularly closely at anything on a millimetre scale.

Thoughts?

[hallucygenia]

I think you're right about many people overlooking the less obvious things. When I first went out trying to find sponges the conversations went thusly:

"Is this a sponge?"
"No, it's a patch of weathering"

"Is this a sponge then?"
"No, it's just a random blob."

"I won't even bother showing you this random weathered blob."
"That's a sponge!"

I think the secret is to look closely at rock surfaces (this is where being short-sighted helps) and take back anything that looks vaguely interesting to be looked at under a microscope. Most things just turn out to be blobs, but occasionally they're interesting.

[Joe Botting]

And here's the promised picture - see? Roy's advice really works! :-)

Has anyone seen the likes of this elsewhere?

i5.photobucket.com/albums/y159/joseph00/holothurian.jpg

[William]

Hi Joe and Others,
Congratulations on this important find. Do you think it is worth mentioning that finds such as this can loose much of their scientific value if they are not carefully handled from the moment of exposing the delicate structure. Consolidants can disturb very fine structures and can be very difficult to reverse. I seldom use them in the field. Bill

[hallucygenia]

Hi William,

You're absolutely right about consolidants - they can cause a lot of problems. They can usually be removed with the right solvent, but this can damage the fossil if it's delicate. I remember trying to look at some of Gertrude Elles's graptolites in a museum collection - she had painted something on to preserve them. Unfortunately sometime over the last century the stuff had turned dark brown, and it was impossible to see the fossils. I will admit to using them occasionally myself, but only when the fossil would fall apart when left - this can happen quite easily with graptolites; the fossil can just flake off the rock.

If you did have to use a consolidant, what would you recommend? I've always used paraloid, which is what museums tend to use for sticking on labels, and can be easily removed with a drop of acetone. I know that there are others out there, but I don't know much about their properties.

Lucy

[Joe Botting]

"I remember trying to look at some of Gertrude Elles's graptolites in a museum collection - she had painted something on to preserve them. Unfortunately sometime over the last century the stuff had turned dark brown, and it was impossible to see the fossils."

Indeed. Believe it or not, she used her nail varnish.

Of course, without the benefit of a century's hindsight, we're really guessing as to how any of the modern consolidants will look in future. I've also heard that paraloid is rather useful, though, and if it does go wrong, it should be easily soluble in ether. Unless the hypothetical colour change is related to a chemical/structural change that affects its solubility, that is...